Electric Motorcycles & Electric Bicycles

Jason ;

This is awesome that you took your first step in not just adopting an electric bike, but also that you are building your own based upon your selection of components.

Keep us apprised on your status of how things are working out, especially the range, charging times, and capacity of your battery packs.

I am curious to know what the battery pack lifespan is based upon your usage model, as well as exactly what batteries are being used (manufacturer part number) and the charging/regulation/safety electronics for the batteries.

Steven

Hi Steven,

That will be no problem, I will do that in future and keep you updated.

I purchased the 52v 20Ah battery from UPS. They use Samsung grade A 2500mah cells with a new version of a 40A BMS.

In future when I do a teardown I will confirm this data with serial numbers.

My usage is taking it out only a few times a week for an hour or two at the moment. I try to keep battery voltage between 50v and 58.8v and always store the battery at around 52v - 53v that is 3.7v to 3.8v per cell.

I did hear of a battery incident from UPS a year or two back from a youtuber but when I did research on this incident it was quite obvious in my opinion there were extreme untruths being told in the story. Apparently they were making a compensation claim against the company.

In any case I wanted to test this company's batterys and quality for myself and test the new version of the BMS for a future video.

This battery is a 52v x 20Ah = 1,040Wh

Charger efficiency is 85 to 90% approx

So lets say full charge is 1200wh = 1.2 kwh of electricity.

That is roughly 20p in the uk for roughly 20 miles of range.

1 penny per mile in electricity cost.

I will have to test this out next time I charge the battery with a power meter.

Jason ;

One of the most important ways to save power is not to use the electric motor for starting and at very low speeds like at a stop at the bottom of a hill.

It's much better to pedal up to your top speed and then hit the switch to activate the electric motor. This is especially true when attempting to go up steep hills in that you want to get your rolling mass into as much rolling momentum as possible and this will reduce large energy drains from the battery pack.

Also there are some systems that you can regenerate energy from the motor when you are going down-hill and especially for steep down hills where the rolling mass will not be slowed by the regenerative charging/braking.

I think that there should also be a power assist mode where both your torque from pedaling *and* the torque from the electric motor can be combined to also lessen the battery loading, but i am not too sure on who and how many bikes are capable of doing this.

Steven

Hi Steven,

Yes this 1500 watt motor makes light work of the steepest hills.

Really happy with the ebike so far and its range.

It has an SW900 LCD controller with multiple levels of pedal assist PAS modes including eco mode.

I have attached the SW900 datasheet for anyone interested.

https://www.gonowelectricbicycles.co.za/pdfs/SW900_manual.pdf

Also mounted a cheap ET8134 Multimeter just to mainly monitor battery voltage and voltage drop under load and battery temperature while riding.

Just a small Update on this Ebike testing.

Specifications:

48v 1500 Watts Voilamart motor- wheel with internal controller. Motor 45 newton meters of torque, Personal tested maximum input voltage of 58.8v using a 52v UPS battery. I have had no problem at all running this motor – wheel with internal controller over the first 100 miles of use.

Max Speed : 43 mph (Fully Tested) This speed was tested at night going down a moderate decline, smooth surface, weather 5 degrees C, moderate wind breeze. Battery Voltage was at approx. 57.5v at time of the speed run.

Battery Specs : Nominal voltage: 52v 20Ah UPS battery pack.

BMS Specs : 52v 40A Max,

Minimum battery voltage cut out 42v

Personal tested max voltage of 58.8v

Battery Range: Approx. 20 miles

(Fully tested) on a 7 mile run. Battery voltage started at 58.3 to 53.8v after 7 miles. My estimation is this will easily accomplish 20 miles + range.

Calculated energy per mile

52v*20Ah = capacity of 1040 Watt hours, 1.04 kWh

Cost of this in the UK in 2022 is 28p per kWh

Charger& efficiency

This Ebike uses a switch mode power supply.

Therefore efficiency should be in the area of 80-90%

1.04 kWh charging with an efficiency of 80% would mean a power loss of 0.208 kWh

So the result in energy cost would be £0.336 pence per full charge. Full charge gives 20 miles + range but lets say 20 miles. £0.336 divided by 20 miles = 0.0168 or 1.68 pence per mile.

Fuel price in UK is £7 per gallon. Average car in UK does 30mpg = £0.23 per mile or 23 pence per mile.

Frame: 6061 Aluminum Tubing Mongoose Frame

Tires: Schwalbe Black Jack 26 x 2.25

Price - cost: £1000

Personal opinions:

Advantages:

This is my first (ebike) and personal opinion is this machine is just simply brilliant. Rough estimation of calculated cost of energy per mile is 1.68 pence per mile at worst. Whereas a car is 23 pence per mile.

Getting around the city on this bike is effortless and much faster than going in a car. No waiting in long cues of traffic with frustrated drivers.

This is simply a joy to ride in summer, getting the fresh air and taking in the scenery.

Everybody loves the bike and is outright shocked by the speed.

Down Sides : No rear suspension, would be nice on next project. Cannot take this ebike out in rain or bad weather as the battery is not rated for all weather. I do however plan on changing this in the near future. Obviously another down side is open to the elements and in cold weather.

Certainly, would not dare to leave this bike anywhere while out due to high risk of theft. Teenagers pay this bike a lot of attention!